Dry eye, also known generically as keratoconjunctivitis sicca and dyslacrima, is a common ophthalmological disorder affecting millions of people. A patient with dry eye may experience burning, a feeling of dryness and persistent irritation. In severe cases, dry eye can seriously impair a person's vision and hence handicap the sufferer in activities such as driving. Certain diseases such as Sjogren's disease manifest dry eye symptoms. Also, as people age, the lacrimal glands in the eye may produce less moisture, resulting in eyes that become dry, inflamed, itchy and gritty.
Although it appears that dry eye may result from a variety of underlying, unrelated pathogenic causes, all presentations of the condition share a common effect, namely the breakdown of the pre-ocular tear film, which commonly results in dehydration of the exposed outer surface and hence the symptoms described above.
A number of approaches exist for the treatment of dry eye. One common approach has been to supplement the ocular tear film using artificial tears instilled throughout the day. Examples of the tear substitute approach include the use of buffered, isotonic saline solutions and aqueous solutions containing water-soluble polymers that render the solutions more viscous and thus less easily shed by the eye by the washing action of the tear fluid. See, for example, U.S. Pat. No. 5,209,927 to Gressel, et al.; U.S. Pat. No. 5,294,607 to Glonek, et al.; and U.S. Pat. No. 4,409,205 to Shively;
Although these approaches have met with some success in some cases, significant challenges in the treatment of dry eye nevertheless remain. Problems include the fact that the use of tear substitutes, while temporarily effective, generally require repeated application over the course of a patient's waking hours, not uncommonly ten to twenty times over the course of a day. Such an approach is not only inconvenient and time consuming, but not very effective in preventing at least the initiation of dry-eye symptoms. Although increasing the viscosity of the dry-eye product may extend the product's duration in the eye or increase in viscosity is effective at extending duration only to a limited extent. Viscous ophthalmic drops are sometimes undesirable because they feel sticky in the eye. Further, increases in the duration of the product would be highly desirable. Carboxymethylcellulose (CMC) is a known viscosifier and demulcent in ophthalmic formulations including formulations for the delivery of a pharmaceutical agent. Polyols including glycerin are known as demulcents and hypotonicity adjusting agents in ophthalmic formulations including formulations for the delivery of a pharmaceutical agent. See EP Publ. No. 538,313 and EP Publ. 592,348 that teach selection of one of several ingredients including carboxymethylcellulose and one of several ingredients including glycerin.
JP Abstract No. 05000951 teaches a drug delivery composition comprising a corticosteroid delivered in a suspending agent (e.g. carboxymethylcellulose sodium and methylcellulose and a suspending assistant (e.g. concentrated glycerol, propylene glycol, glucose or lactose).
In view of the above, it would be desirable to provide an eye-drop solution that is optimized in its ability to last longer in the eye and/or will better alleviate the symptoms of dry eye. An ophthalmic dry eye solution that is safe, convenient and economical to use is also desireable. In particular, it would be highly desirable to develop a product having significantly greater duration of efficacy, in order to significantly decrease the number of times that the product may need to be administered to the eye, over the course of a day, in order to effectively treat the symptoms of dry eye. The present invention addresses some or all of these and/or other needs.
U.S. Pat. No. 5,106,615 discloses the combination of a polyol with a carbomer polymer the invention is a long-lasting dry eye formula.